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====== Int 21H, AH=44H, AL=09H ======

===== Version =====

3.1 and higher

===== Brief =====

CHECK IF BLOCK DEVICE REMOTE

===== Family API =====


===== Input =====

	AX = 4409h
	BL = drive number (00h = default, 01h = A:, etc)

===== Return =====

 CF clear if successful
	    DX = device attribute word
		bit 15: drive is SUBSTituted
		bit 13: (DR DOS 3.41/5.0 local drives only) always set
			media ID needed
		bit 12: drive is remote
		bit  9: direct I/O not allowed
	CF set on error
	    AX = error code (01h,0Fh,15h) (see #01680 at AH=59h/BX=0000h)

===== Macro =====


===== Notes =====

on local drives, DX bits not listed above are the attribute word from the device driver header (see #01646 at AH=52h); for remote drives, the other bits appear to be undefined for MS-DOS versions prior to 5.0 (they are all cleared in DOS 5+)

checking whether DX=0800h on return appears to be a fairly reliable method for detecting Microsoft's RAMDRIVE, though not for other ramdisks (there appears to be no simple yet foolproof method for detecting ramdisks, although the presence of only a single copy of the FAT and only a single head on non-removable devices is a fairly good indicator); for Windows95, RAMDRIVE returns DX=4800h

for non-existent remote drives, this function sometimes returns AX=0015h (drive not ready) instead of AX=000Fh (invalid drive) on the first call; a subsequent call will return the correct error code

this function was not supported by Digital Research's DOS Plus

===== See also =====

AX=[[en:docs:dos:api:int21:44:00|4400h]],AX=[[en:docs:dos:api:int21:44:08|4408h]],AX=[[en:docs:dos:api:int21:44:0a|440Ah]],INT 2F/AX=122Bh

===== Note =====

Text based on [[http://www.cs.cmu.edu/~ralf/files.html|Ralf Brown Interrupt List Release 61]]

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